Method and arrangement for authenticating a control unit and transmitting authentication information messages to the control unit

A system for authenticating a maintenance and diagnostics service computer for connection to a printing or a copying system to be serviced by performing maintenance and diagnostics, comprising:

• an authentication server which generates a transaction information and delivers via a first communication line the transaction information to a user of said maintenance and diagnostics service computer, said transaction information being entered by the user of the service computer into the service computer in order to execute authentication of the service computer;
• said service computer generating first data with aid of the transaction information, said first data including a hardware identifier of hardware contained in the service computer;
• said service computer transmitting via a second communication line which is distinct from the first communication line said first data from the service computer over to the authentication server over second communication line comprising a data line;
• said authentication server generating key data depending on the first data and transferring the key data from the authentication server to the service computer over the data line, said key data defining said access rights of the service computer;
• said service computer generating authentication information for authenticating the service computer with aid of the key data;
• said service computer transmitting the authentication information from the service computer directly to a system control unit of said printing or copying system independently of the authentication server and after receiving the key data from the authentication server;
• said system control unit verifying authenticity of the service computer;
• and
• said system control unit checking said access rights defined by the key data of the service computer and if access is authorized, servicing by performing said maintenance and diagnostics on the printing or copying system with the maintenance and diagnostics service computer.